In a wireless communication system, various schemes for enhancing system performance have been proposed. One of the various schemes proposed for enhancing system performance is a scheme of mitigating interference.
Various schemes of mitigating interference have been proposed, and a typical one is an interference whitening scheme is a typical example. For example, an interference whitening scheme used in a long-term evolution (LTE) mobile communication system will be described below. For convenience, the interference whitening scheme used in the LTE mobile communication system will be referred to as LTE interference whitening scheme.
An LTE interference whitening scheme is a scheme of detecting statistical characteristics (e.g., a variance matrix of an interference signal (IS) using a plurality of samples such as a reference signal (RS) (e.g., a common reference signal (CRS), or a demodulation reference signal (DMRS), and mitigating an interference signal based on, for example, a minimum mean square error (MMSE) scheme. For example, interference signal measurement for an RS (e.g., CRS, or DMRS) may be mainly performed on a sub-frame basis because the interference signal measurement for the RS may be performed on a sub-frame basis is that a base station (BS) allocates a resource on a sub-frame basis in the LTE mobile communication system.
Recently, in the LTE mobile communication system, a case that synchronization difference among transmitted signals of BSs in one terminal is equal to or greater than several symbols due to various parameters (e.g., network delay among the BSs, or signal transmission delay according to distance difference per BS), which frequently occurs in an actual field, are newly recognized as an issue.
In a case that synchronization difference among transmitted signals of BSs in one terminal is equal to or greater than several symbols, if an interference is measured on a sub-frame basis like in the LTE interference whitening scheme, the measured interference may be inaccurate. Thus, severe reception performance degradation may occur on data by interference signals not synchronized due to the inaccurate interference measurement.
A scheme of effectively mitigating interference in a wireless communication system is desired.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determinations and no assertions are made as to whether any of the above might be applicable as prior art with regard to the present disclosure.